IP Annals of Prosthodontics and Restorative Dentistry 2021;7(2):97–100
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IP Annals of Prosthodontics and Restorative Dentistry
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Case Report
Prosthodontic rehabilitation of residual mandibular defect with Fixed removableHybrid prosthesis- A case report
Mahesh Gowda1, Poonam Prakash2,*, NK Sahoo1
1Dept. of Prosthodontics and Crown & Bridge, Command Military Dental Centre, Pune, Maharashtra, India2Dept. of Prosthodontics and Crown & Bridge, Armed Forces Medical College, Pune, Maharashtra, India
Ameloblastoma is a rare, benign tumor of odontogenic epithelium that was recognized in 1827 by Cusackand renamed ameloblastoma in 1930 by Ivey and Churchill. Ameloblastomas can be found both in themaxilla and mandible with a greater predilection of about 80% in the mandible with the posterior ramusarea being the most frequent site. While chemotherapy, radiation therapy, curettage and liquid nitrogen havebeen effective in some cases of ameloblastoma, surgical resection remains the most definitive treatment forthis condition. Rehabilitation of residual mandibular defect post resection is a challenge due to long spancompromised ridge condition and the absence of dentition. In such scenario, a fixed-removable prosthesisallows rapid return to excellent function by providing favorable biomechanical stress distribution alongwith restoration of esthetics, phonetics and ease of postoperative care and maintenance.This paper presents successful Prosthodontic rehabilitation of a patient with a large residual mandibulardefect secondary to surgical resection for ameloblastoma using fixed-removable hybrid prosthesis.
Mandibular defects are generally acquired, usuallyoccurring secondary to tumour resection. The most commonodontogenic tumour of the mandible is Ameloblastomawhich is unicentric, non-functional, intermittent in growth,anatomically benign and clinically persistent. This tumouris locally invasive, produces marked deformity and seriousdebilitation and has a remarkable recurrence rate aftersurgery.1Marginal en block resection with excision of someamount of clinically normal bone is the most commonlyemployed approach that results in a predictable outcome.2
A recent meta-analysis revealed that the risk of recurrencewas 3.15-fold greater with conservative treatment incomparison to resective treatment.3
Surgical resection leaves behind a residual mandibulardefect that impairs mastication, deglutition and speech.The objectives of post surgical Prosthodontic rehabilitation
in such cases are to restoration and maintenance of oralfunction, enhancing the comfort and improvement in theappearance.
Prosthodontic rehabilitation of these large residualintra oral defects involves diverse techniques and variedprostheses and the choice of restoration depends uponmultiple factors such as residual dentition, residual bonydefect, anatomical relationship of the mandible to maxillaand also patient’s choice. Multiple prosthetic options areavailable for rehabilitation but due to size and type of defect,a hybrid prosthesis is a preferred option.
This paper presents successful Prosthodonticrehabilitation of a patient with a large residual mandibulardefect using hybrid prosthesis.
2. Case Report
A 66 years old female patient reported with chief complaintof swelling in left lower mandibular region. Clinicalexamination revealed the swelling of approximately 5 x
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3 cm in relation to premolars and molars with diffusemargins [Figure 1]. Clinico-radiological examination ledto a provisional diagnosis of unicystic ameloblastomamandible (left) extending from the first premolar tothe second molar. Treatment plan formulated was toperform En block resection of mandible sparing the lowerborder of mandible by Maxillofacial Surgeon followed byProsthodontic rehabilitation [Figure 2].
2.1. Examination, diagnosis and treatment planning
After three months of adequate healing, patient reportedto us due to difficulty in eating from right side. Clinicaland radiological examination revealed missing dentition(34, 35, 36, 37) along with an residual mandibular defect[Figure 2]. The mandibular defect was classified as Cantor& Curtis class I in which radical alveolectomy was donealong with preservation of mandibular continuity. Thetreatment options explored were; removable partial dentureand an implant supported FDP after bone augmentation.Conventional tooth supported FDP was ruled out dueto length of edentulous span and size of the residualmandibular defect which would have unfavourable longterm prognosis. Implant supported FDP was eliminateddue to patient’s unwillingness for any additional surgicalintervention. Detailed clinical evaluation revealed a longspan edentulous region approximately 15 mm and soundabutments (32, 33, 38) teeth with no signs of clinicalmobility. Based on the clinical condition and patient’sdesire, a rehabilitation plan was formulated to replace themissing dentition and alveolar ridge with a fixed removablehybrid prosthesis. The procedure was explained to thepatient and an informed consent was obtained.
2.2. Prosthodontic rehabilitation phase
A fixed removable hybrid prosthesis was planned as thedefinitive treatment comprising of porcelain fused to metalrestorations utilising lower left lateral incisor, canine andthird molar as abutments and a removable prosthesis overthe metal framework.
Diagnostic impressions of both the arches were madewith irreversible hydrocolloid impression material (Zelgan2002 Dentsply) and study casts obtained. Diagnostic mock-up was done over which a putty index was made usingPolyvinylsiloxane impression material (Express VPS, 3MESPE). The wax up facilitated fabrication of provisionalrestorations and determination of optimal position of theAndrews bar in the definitive prosthesis.
The abutment teeth (32,33 & 38) were prepared[Figure 3]. Two‑stage putty light body impressionof the mandibular arch was made and poured in diestone. Provisional prosthesis was fabricated using the puttyindex and cemented with eugenol free provisional lutingagent(GC Freegenol). Wax pattern was fabricated with
four custom made bar and precision attachments in theregion of premolars and molars. The putty index wasused to determine the position and angulation of the bar.The wax pattern was sprued, invested and cast usingnickel–chromium (Ni‑Cr) alloy. The frameworkwas retrieved and finished. Parallelism was ensured betweenanterior and posterior retainers (distal surface of 33 &mesial surface of 38) to create guide planes for removabledenture. Framework was tried intraorally to assess fit andavailability of interarch space. Following this, ceramicveneering was done for both the anterior retainers. Themetal framework with auxiliary attachment was cementedusing Type I Glass ionomer luting agent[Figure 3].
After cementation of the framework, impression of themandibular arch was made using irreversible hydrocolloidand cast was fabricated. Maxillomandibular relations wererecorded, teeth arrangement done and processing wasdone using heat polymerized high strength acrylic resin.Laboratory remounting and finishing and polishing of theprosthesis were carried out. The undercuts in the prosthesiswere removed before insertion and removable denture wasplaced on the framework over the attachment [Figure 4].The denture was evaluated and occlusal contacts adjusted.Post insertion, hygiene and home care instructions wereexplained and the placement and removal of the prosthesiswas demonstrated. Regular follow ups at first week, fourweeks and 3 months were carried out with no loss ofretention and adaptability of definitive prosthesis.
Fig. 1: Intraoral left lateral occlusal and per surgical view
3. Discussion
Loss of bony segments and normal tissue anatomy asa result of the surgical resection of oral tumors oftenpresents a challenge in the functional rehabilitation ofthe patient. Multiple prosthetic options are available forrehabilitation of residual mandibular defects that includeremovable partial denture (RPD), fixed dental prosthesis(FDP) or an implant retained prosthesis. However, FDPand implant retained prosthesis are not always feasible dueto compromised alveolar morphology, especially in largedefects. In such situations, hybrid prosthesis with teeth
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Fig. 2: Post Op OPG
Fig. 3: Intraoral mandibular defect view with prepared abutmentsand Cemented metal framework
Fig. 4: Fixed removable Hybrid prosthesis insitu
supported metal frame work supporting removable partialdentures is an option that combines the advantages offixed prosthesis (support, stability, and retention) removableprosthesis (esthetics and hygiene maintenance).4
In the case presented, FDP was ruled out, as it wouldhave compromised esthetics and biomechanics due tooverlay of long pontics and long span of the defect.Considering the available bone length and bone graftprocedures required, the placement of an implant was aquestionable option.Considering the defect size which wasgreater than 15 mm, age and desire of the patient, hybridprosthesis was selected.
Dr. James Andrews introduced the hybrid prosthesiswhere fixed bridge is made of porcelain fused to metalcrowns along with a bar and attachment studs whichis permanently cemented to the prepared abutment. Theremovable portion is made of acrylic and is retained onto a fixed bar.5Various advantages of Andrews’s bridge as
reported in literature are better esthetics, adaptability andphonetics, economical, retention, comfort to the patient andstability with minimal extension. It acts as stress breaker andavoids transfer of unwanted leverage forces to the abutmentteeth. Cheatham and Mueninghoff reported that the hybridprosthesis is generally indicated when the placement ofthe conventional FDP would compromise esthetics and thedefect has a greater loss of alveolar ridge and soft tissue.6,7
Shetty and Patel have described techniques using Andrew’sbar system for oral rehabilitation of missing anterior teethwith ridge defect.8,9 Wangoo has elaborated techniquesusing either prefabricated or custom made attachments fororal rehabilitation of missing teeth with ridge defects.10,11
4. Conclusion
The technique and rationale of hybrid prosthesis hasbeen discussed, wherein a large mandibular defect wasrehabilitated with a fixed removable hybrid prosthesis thatproduced optimum functional and aesthetic results. Thisprosthesis allowed the pontic to be entirely ridge borne (onlyretained and stabilized by bar) and combined advantagesof both fixed and removable prostheses ie; withstandingthe masticatory forces that develop during function withoutcompromising esthetics, phonetics, comfort and hygiene.
5. Source of Funding
No financial support was received for the work within thismanuscript.
6. Conflict of Interest
The authors declare they have no conflict of interest.
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In: 12th Edn. Elsevier Mosby; 2011.2. Carlson ER, Marx RE. The Ameloblastoma: Primary, Curative
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9. Shetty PK, Shetty BY, Hegde M, Prabhu BM. Rehabilitation oflong-span Kennedy class IV partially edentulous patient with acustom attachment-retained prosthesis. J Indian Prosthodont Soc .2016;16(1):83–6. doi:10.4103/0972-4052.155045.
10. Patel H, Patel K, Thummer S, Patel RK. Use of precision attachmentand cast partial denture for long-span partially edentulous mouth - Acase report. Int J Appl Dent Sci. 2014;1:22–7.
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Author biography
Mahesh Gowda, Professor
Poonam Prakash, Associate Professor
NK Sahoo, Commandant
Cite this article: Gowda M, Prakash P, Sahoo NK. Prosthodonticrehabilitation of residual mandibular defect with Fixed removableHybrid prosthesis- A case report. IP Ann Prosthodont Restor Dent2021;7(2):97-100.
